Chore: To add DataStreamsFeed.sol sample contracts

[woogieboogie-jl]

Hi @woogieboogie-jl

Thank you for your contribution. We've fixed some of the issues identified in your PR in the previous PR #17 which is currently undergoing security review.

We will merge it soon and ask you to rebase you PR and only pick the things which are not already fixed by the previous pr.

Hey team, do check if you can include the contracts (business reasons)

Two quick README tweaks in this PR:

Example receiver contract added
• contracts/DataStreamsFeed.sol – Adrastia’s community implementation of a Data Streams feed reader.

Safety notice
• README now highlights that the sample contract is unaudited and ships without OZ / Chainlink deps or deployment scripts; you must install the libraries and assess risk on your own.

Tiny change, but it should save newcomers a lot of setup questions.

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  • https://app.asana.com/0/0/1211061404520983

[woogieboogie-jl]

Updated sample contracts - with up-to-date features and audit fixes - refer to the most updated contract in this repo

Regarding the contract change themselves - changes applied to this contract after initial audits are:

#1 and #2